834 FOODS AND FOOD ADULTERANTS. 



DETECTION OF VEGETABLE WAX IN BEESWAX.* 



Rabineaud's t method is based on the varying solubilities of different waxes in ether. 

 One part of wax is placed in 50 parts of ether and the whole shaken occasionally. 

 When the pieces of wax have disappeared and a voluminous precipitate taken their 

 place, this last is filtered into a weighed filter, washed with cold ether, the ether 

 allowed to spontaneously evaporate and the filter and contents weighed. Beeswax 

 should leave 50 per cent residue, vegetable wax (Japan wax) 5 per cent Dullo j: says, 

 however : " It is not true that Japan wax (improperly 'plant wax ') is always soluble 

 in ether. There are several kinds of wax called ' vegetable wax ' in trade, and while 

 it is quite possible that there are kinds nearly completely soluble, still this can 

 seldom be the case. Out of six varieties which I have examined not one has com- 

 pletely dissolved, but all have conducted themselves like beeswax with ether. 

 Usually a trifle over 50 per cent has dissolved, but not very much more. A sample of 

 wax containing over 50 per cent of Japan wax given me for investigation behaved 

 with ether like pure wax." 



Four samples of Japan wax were examined. One left a residue, causing slight 

 opalescence of the solution but unweighable, the other three dissolved completely. 

 As, however, other substances used in adulterating beeswax such as stearin (stearic 

 acid) paraffin, rosin, and tallow (but not ceresin) are soluble in cold ether, this method 

 is of little value as far as the detecting of vegetable wax (Japan wax) alone goes. 

 If, however, the fact of the adulteration by this wax alone were established other- 

 wise, this method could be used for an approximation of its extent, inasmuch as all 

 pure beeswax samples behave nearly alike toward ether. 



Dullo says (I.e.): "The best method for the detection of Japan wax is: Boil to- 

 gether 10 grams of the suspected wax in 120 grams water and 1 gram soda (accord- 

 ing to others 1 gram caustic potash) for one minute. If Japan wax is present, there 

 is formed a soap, which on cooling becomes gradually solid or thick. Boiling for so 

 short a time and with such a dilute alkali solution does not saponify beeswax, 

 which separates at the surface of the liquid with its natural hardness and consistence. 

 The soap produced by Japan wax is materially different from that produced from 

 stearin and soda. The latter is slimy and gelatinous while the former is a magma of 

 fine granules. The one can not be mistaken for the other by any one who has seen 

 both. The Japan wax soap requires much alcohol, and must be heated before it 

 will dissolve, and, on cooling, a portion of the wax separates, but the solution of 

 the remainder does not solidify. For solution of sodic stearate, little alcohol and not 

 much heat are required, but the solution ultimately solidifies even when quite di- 

 lute." 



According to investigations made, this method is useless, no matter whether soda 

 or caustic potash be used. Pure beeswax heated this way gives a thick milky solu- 

 tion, and no such thing as a solid wax cake separates. 



Hager says " the presence of Japan wax is established when a wax which is mostly 

 soluble in chloroform to a clear solution is heavier than 0.980." Ch. Me"ne|| says, 

 " the detection of Japan wax in beeswax is only possible by means of the specific 

 weight, and is not possible by means of determining either crystallization point or 

 melting point. But reliance on specific gravity alone is unsafe." 



In another article HagerT says, " the detection of Japan wax is easily accomplished 

 by boiling .300 to .400 gram of wax in a solution of .500 gram borax in 6 to 8 cc 

 water, shaking occasionally. The resultant cloudy solution on standing gradually 



* H. Rottger, Chem. Zeit., 1890, 85, 1442, do. 87, 1473. 



tFres. Zeit. f. a. Chein., 1862, 115; Dingl. polyt. Jour., 1862, 163, 80. 



t Dingl. polyt. Jour., 1864,172-156. 



$ Comm. Pharm. Germ., 1873, 436. 



|| Dingl. polyt. Jour., 1874, 214-87. 



If Chem. Zeit., 1890, 14-606. 



